Ultraprocessed Foods Linked To Silent Strokes, Hidden Brain Damage

Highest Ultraprocessed Food Intake Linked to 40% Higher Odds of Silent Brain Injury

People who ate the most ultraprocessed food had 40% higher odds of silent brain injury than those who ate the least, according to a new study. That damage, small signs of harm to blood vessels in the brain, shows up only on an MRI scan and can go unnoticed even when memory and thinking seem fine.

Researchers analyzed 8,783 middle-aged adults in Canada. Those who ate the most ultraprocessed food, items like packaged snacks, sugary drinks, and ready-made meals, also carried more body fat and more fat around their organs than those who ate the least. Brain injury appeared in about 8% of people in the lowest intake group, compared with more than 11% in the highest, according to results published in JAMA Network Open.

Brain scans showed more injury at the top of the intake range, yet memory and thinking test scores barely differed across the four groups. Senior author Sonia Anand said the link between diet and brain health “may be detectable before people experience noticeable problems with memory or thinking.” First author Russell J. de Souza said such damage is usually tied to conditions “we hear about and treat at a much older age.”

Ultraprocessed Food Supplied 42% of Calories for Nearly 9,000 Canadian Adults

Scientists combined data from two Canadian health studies. Participants were 35 to 69 years old, averaged about 58, and had no heart disease. Women made up 56.6% of the group, and most participants were White European.

Participants described their eating over the past year on detailed questionnaires, and researchers sorted those foods using a system that separates whole or lightly processed items from heavily manufactured products loaded with additives. On average, ultraprocessed foods supplied about 42% of daily calories. Participants were split into four equal-sized groups by intake, then compared after accounting for age, sex, ethnicity, income, education, exercise, smoking, total calories, and conditions like diabetes and high blood pressure.

Testing included a body fat measurement, scans measuring fat around internal organs and in the liver, and detailed brain MRIs reviewed by neurologists who did not know anything else about them. Not every measurement was available for every person. Brain scans looked for two warning signs: tiny spots left by past blocked blood flow, known as silent strokes, and bright spots signaling damage to the brain’s smallest blood vessels. Both counted as brain injury. Two standard tests measured overall mental sharpness and how fast people process information.

Highest Ultraprocessed Food Group Carried More Body Fat and Organ Fat

Body fat ran about 1.7 percentage points higher in the highest group than in the lowest, while liver fat did not differ. Fat stored deep in the belly is tied to inflammation and blood vessel damage that can reach the brain too, which makes it a plausible link between diet and brain injury.

That 40% jump in brain injury odds appeared only when intake was counted in servings per 2,000 calories, a standard day of eating. When researchers measured ultraprocessed food as a share of total calories instead, the brain injury link was too weak to rule out chance, as the authors note.

Brain injury odds climbed more in women than in men. Women in the highest group had 78% higher odds than women in the lowest, while men showed no clear pattern. Because this comparison was unplanned, the authors say other studies need to confirm it.

A few secondary analyses showed slightly better thinking scores among heavier consumers. The authors said that may reflect chance, measurement error, or many participants scoring near the top of the tests, and cautioned against reading it as a benefit.

Heavy Ultraprocessed Food Eaters Still Ate Vegetables and Whole Grains

Higher ultraprocessed food intake did not come with fewer vegetables. Daily vegetable servings rose across the groups, as did whole grains and dairy, while fruit servings dipped in the highest group. Whole and minimally processed foods did shrink as a share of daily servings, from 68.6% in the lowest group to 41.5% in the highest, largely because total servings grew. The authors say the pattern is unlikely to come down to food groups alone. That raises the possibility that something about the processed products themselves, whether their sugar content, their effect on appetite, or other factors tied to how they are made, could be contributing.

Everything was measured at a single point in time rather than tracked over years, so the study cannot show that ultraprocessed food causes brain injury, or rule out that cause and effect run the other way. Heavier consumers also tended to have lower incomes, less exercise, and higher rates of diabetes and high blood pressure. Adjustments covered those factors, but unmeasured ones could remain.

Brain Scans Showed an Ultraprocessed Food Link Memory Tests Did Not

Silent brain injuries seen on MRI have been tied in other research, cited by the authors, to later stroke and cognitive decline. Whether cutting back on ultraprocessed food would lower the odds is unknown. Still, if early vessel damage can build while thinking stays intact, middle age looks like a sensible time to pay attention to what fills the grocery cart.

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Disclaimer: This article is for informational purposes only and is not medical advice. The study reports associations and cannot prove that ultraprocessed food causes brain injury. Anyone with questions about diet or brain health should consult a doctor or other qualified health professional.

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